My solution to this Guardian puzzle (my solution was highlighted 🎉): https://www.theguardian.com/science/2020/jan/13/did-you-solve-it-the-poco-poco-puzzle#comment-137362390

pocomucho_puzzle.js

// https://www.theguardian.com/science/2020/jan/13/did-you-solve-it-the-poco-poco-puzzle#comment-137362390
// I did it with code!

var P, O, C;
var M, U, _C, H, _O;

var greatSuccess = false;

var result;

// Just some colours for pretty printing results
const col = {
    reset: '\033[0m',

    //text color

    black: '\033[30m',
    red: '\033[31m',
    green: '\033[32m',
    yellow: '\033[33m',
    blue: '\033[34m',
    magenta: '\033[35m',
    cyan: '\033[36m',
    white: '\033[37m',

    //background color

    blackBg: '\033[40m',
    redBg: '\033[41m',
    greenBg: '\033[42m',
    yellowBg: '\033[43m',
    blueBg: '\033[44m',
    magentaBg: '\033[45m',
    cyanBg: '\033[46m',
    whiteBg: '\033[47m'
}

var cO = col.red
    cC = col.yellow;

console.log(     "\n       " + "P " + cO + "O " + cC + "C " + cO + "O" + col.reset);
console.log("     " + "M " + "U " + cC + "C " + col.reset + "H " + cO + "O" + col.reset);
console.log("______________");

for (P = 0; P < 10; P++) {
  
  for (O = 0; O < 10; O++) {

    for (C = 0; C < 10; C++) {

      // We're looking for:
      // 15 * POCO
      //   = MUCHO
      //
      // where each letter stands for a unique digit

      greatSuccess = false;

      result = "" + (15 * ("" + P + O + C + O));

      M  = result.charAt(0); M = M ? M : 0;
      U  = result.charAt(1); U = U ? U : 0;
      C_ = result.charAt(2); // C in results
      H  = result.charAt(3); H = H ? H : 0;
      O_ = result.charAt(4); // O in results

      greatSuccess = (
        result.length == 5 
        && C_ == C 
        && O_ == O
        && noDuplicatedChars("" + P + O + C + M + U + H)
      );
      
      if (greatSuccess) {   
        console.log(      "\n15 x   " + P + " " + cO + O + " " + cC + C + " " + cO + O + col.reset);
        console.log("   = " + M + " " + U + " " + cC + C_ + col.reset + " " + H + " " + cO + O_ + col.reset);
      }
    }
  }
}

function noDuplicatedChars(str) { 
  const chars = new Set();

   for (let c of str) { 
    if (chars.has(c)) return false; 
    chars.add(c);
   } 
   return true; 
}

console.log(col.white + col.greenBg+"\ndone.\n");

// Result:
//  15 x 4595 = 68925

pocomucho_puzzle.py

# Python implementation
# Credit: Dick Pountain #comment-137361347

for p in range(0, 10):
  for o in range(0, 10):
    for c in range(0, 10):
      if p != o and p != c and c != o:
        z = (p * 1000 + o * 100 + c * 10 + o) * 15
        for m in range(0, 10):
          for u in range(0, 10):
            for h in range(0, 10):
              x = m * 10000 + u * 1000 + c * 100 + h * 10 + o
              if z == x and m != u and m != h and h != u and m != c and h != c and u != c and h != o and u != o and u != p and m != p and h != p:
                print(p, o, c, o, ' ', m, u, c, h, o)